XPS and AFM characterization of aminosilanes with different numbers of bonding sites on a silicon wafer

The aim of this work was the preparation and characterization of a silicon surface modified by different self-assembled aminopropylsilanes with the purpose of using them in sensor applications. Single-crystal silicon wafers (111) were modified with aminosilanes that have different numbers of bonding sites: 3-aminopropyltrimethoxysilane (APTMS), 3-aminopropyldiethoxymethylsilane (APRDMS) and 3-aminopropylethoxydimethylsilane (APREMS). We deposited the self-assembled layers from a solution of aminosilanes in toluene under various reaction conditions. The surface composition and the chemical bonding were determined using X-ray photoelectron spectroscopy. Furthermore, the surface morphology was investigated using atomic force microscopy. Our results show that the reactivity with the Si-oxide layer and the polymerization of aminosilanes depend on the number of possible bonding sites. The APTMS reacted the most intensively with the Si-oxide layer; a less intensive reaction was observed for the APRDMS; and the least intensive reaction was observed for the APREMS. Copyright (c) 2013 John Wiley & Sons, Ltd.